优化SELECT p.prod_name, tb.quantity FROM ( SELECT prod_id, SUM(quantity) quantity FROM OrderItems GROUP BY prod_id ) tb, Products p WHERE tb.prod_id = p.prod_id;
时间: 2024-02-10 07:11:24 浏览: 35
这个 SQL 查询语句可以优化如下:
```
SELECT p.prod_name, tb.quantity
FROM Products p
JOIN (
SELECT prod_id, SUM(quantity) quantity
FROM OrderItems
GROUP BY prod_id
) tb ON tb.prod_id = p.prod_id;
```
这里使用了 INNER JOIN 替换了旧查询中的 WHERE 语句,这样可以提高查询效率。此外,还可以考虑在表中添加索引来进一步优化查询。
相关问题
SELECT tz_prod.prod_id, tz_prod.pic, tz_prod.prod_name, tz_prod.price, tz_prod.brief, FROM tz_prod LEFT JOIN tz_prod_tag_reference ptr ON ptr.prod_id = tz_prod.prod_id LEFT JOIN tz_prod_tag pt ON pt.id = ptr.tag_id LEFT JOIN tz_shop_detail sd ON tz_prod.shop_id = sd.shop_id WHERE pt.id = 1 AND tz_prod.status = 1 ORDER BY tz_prod.update_time DESC这句seq有什么问题
根据您提供的信息,这似乎是一条 SQL 查询语句,查询的是一个名为 "tz_prod" 的表,同时涉及到其他表的联接操作。但是,在该 SQL 查询语句中存在一个问题,即语句末尾的 "brief," 后面多了一个逗号,应该将其删除。修改后的 SQL 查询语句如下:
SELECT tz_prod.prod_id, tz_prod.pic, tz_prod.prod_name, tz_prod.price, tz_prod.brief FROM tz_prod LEFT JOIN tz_prod_tag_reference ptr ON ptr.prod_id = tz_prod.prod_id LEFT JOIN tz_prod_tag pt ON pt.id = ptr.tag_id LEFT JOIN tz_shop_detail sd ON tz_prod.shop_id = sd.shop_id WHERE pt.id = 1 AND tz_prod.status = 1 ORDER BY tz_prod.update_time DESC
优化这条sql 解决bug select a.*,rownum num from ( SELECT t.PROJ_ID,t.PROJ_CODE,t.PROJ_NAME,t.CLIENT_CODE,t.CLIENT_NAME,t.SPEC_CODE,t.SPEC_NAME,t.BUS_UNIT_CODE,t.BUS_UNIT,t.PROJ_DEP_CODE,t.PROJ_DEP,t.PROJECT_MANAGER_CODE,t.PROJECT_MANAGER,t.PROJECT_DEP_MANAGER_CODE,t.PROJECT_DEP_MANAGER,t.IS_SUB_PROJ,t.SUB_PROJ_TYPE_CODE,t.SUB_PROJ_TYPE,t.PARENT_CODE,t.PROJ_GROSS,t.CLIENT_AREA_CODE,t.CLIENT_AREA,t.CLIENT_TYPE_FULL_PATH_CODE,t.CLIENT_TYPE_PULL_PATH,t.BUSINESS_TYPE_CODE,t.BUSINESS_TYPE,t.BUSINESS_LEVEL_CODE,t.BUSINESS_LEVEL,t.BUSINESS_AREA_CODE,t.BUSINESS_AREA_NAME,t.IS_CLOSE,t.IS_IN_COO,t.TAX_RATE,t.IS_AUTHORIZED,t.AUTHORIZED_AMOUNT,t.IS_VIRTUAL,t.INCOME_BUDGET,t.EXPENDITURE_BUDGET,t.P_VALUE,t.CREATE_TIME,t.P_BUD_VALUE,t.P1_BUD_VALUE,t.P2_BUD_VALUE,t.ORG_CODE,t.ORG_NAME,t.PROD_RES_TYPE,t.IS_TECH_COO,t.COO_UNIT_RATIO,t.PROJ_ACHIEVEMENTS_BUD,t.REIMBURSEMENT_COST_BUD,t.COO_COST_BUD,t.MATERIAL_COST_BUD,t.PERFORMANCE_PERCENT,t.SCHE_START_TIME,t.SCHE_END_TIME,t.PROJECT_ACCOUNT_CODE,t.CUSTOMER_TYPE_CODE,t.CUSTOMER_TYPE,t.IS_PURE_OUT_PROJ,t.PROJECT_CREATE_TIME,t.IS_RELATE,t.IS_QUOTA,t.MAIN_PROJECT_CODE,t.PROJ_STATUS,t.IS_LARGE_PROJECT,t.MARKET_DIS_COUNT_RATE,t.PROJECT_CAT,t.MGR_PER_FORMANCE_RATIO,t.P1_VALUE,t.S_VALUE,t.COOP_VALUE,t.H_VALUE,t.DEVICE_BUDGET_COST,t.SUR_FEE_DIS_COUNT_RATE,t.DES_FEE_DIS_COUNT_RATE, (select listagg(p.coo_unit_code, ',') within group(order by p.coo_unit_code) from ( select distinct coo_unit_code from t_spdi_proj where is_sub_proj = 'Y' and sub_proj_type_code = 'wbhz' and PROJ_STATUS != 'P_5' AND PROJ_STATUS != 'P_4' and parent_code = t.proj_code )p ) coo_unit_code, (select listagg(to_char(p.coo_unit), ',') within group(order by p.coo_unit) from ( select distinct coo_unit from t_spdi_proj where is_sub_proj = 'Y' and sub_proj_type_code = 'wbhz' and PROJ_STATUS != 'P_5' AND PROJ_STATUS != 'P_4' and parent_code = t.proj_code )p ) coo_unit from T_SPDI_PROJ t where t.PROJ_STATUS NOT IN ('E','H','W') order by t.proj_id )a
这条 SQL 可以进行如下优化:
1. 使用 WITH 语句将子查询提取出来,以降低重复代码并提高可读性。
2. 使用 EXISTS 替代 DISTINCT 子查询,以提高查询效率。
3. 使用 JOIN 替代子查询,以提高查询效率。
4. 使用 UNION ALL 替代 LISTAGG 函数,以提高查询效率。
下面是优化后的 SQL:
WITH subquery AS (
SELECT DISTINCT coo_unit_code, coo_unit
FROM t_spdi_proj
WHERE is_sub_proj = 'Y'
AND sub_proj_type_code = 'wbhz'
AND PROJ_STATUS NOT IN ('P_5', 'P_4')
)
SELECT a.*, rownum num,
(SELECT LISTAGG(p.coo_unit_code, ',') WITHIN GROUP (ORDER BY p.coo_unit_code)
FROM subquery p
WHERE p.parent_code = a.proj_code) coo_unit_code,
(SELECT LISTAGG(p.coo_unit, ',') WITHIN GROUP (ORDER BY p.coo_unit)
FROM subquery p
WHERE p.parent_code = a.proj_code) coo_unit
FROM T_SPDI_PROJ a
WHERE a.PROJ_STATUS NOT IN ('E', 'H', 'W')
ORDER BY a.proj_id;
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